Abstract: This article made a systematic and deep research on the property of soybean polyphenol oxidase and soybean peroxidase,including the function of the activity of polyphenol oxidase,heat stability,pH value as well as the inhibiting effect of soybean lecithin and dimercaprol.The result showod that the activity of polyphenol oxidase reached irreversible status at the temperature of 120℃.When pH value was between 6－7,the enzymatic activity was the highest .As the concentration of dimercaprol was 1.5m mol/L the activity of enzyme droped to as low as 6％.Soybean peroxidase showed a strong heat resistance .The proper pH value was 5.5.When the concentration of soybean lecithin reached 80mg/L,the activity of enzyme declined around 20％.

Key words: Soybean Polyphenol Oxidase Soybean Peroxidase Enzymatic Activity Enzymatic Heat Stability Inhibiting effect Soybean lecithin Dimercaprol